In the mobile internet field, both of the 3rd Generation (3G) and the Wireless Local Area Network (WLAN) belong to the current technique hotspots. The 3G is a global roaming mobile communication network which is able to provide various types of high quality multimedia services, and the main technical standards include the Wideband Code Division Multiple Access (WCDMA), Code-Division Multiple Access 2000 (CDMA2000) and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), and the 3G mainly provides Internet services, private network access services, WAP/BREW/JAVA based services and multimedia communication services and so on.
The WLAN is able to provide high speed wireless access in a smaller area, and is used for transmitting Internet Protocol (IP) packet data packets. At present, the main technical standards include 802.11b, 802.11a and 802.11g, which are all based on the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) technique, wherein 802.11b is currently the most widely applied domestic standard, which is also called the Wireless Fidelity (WIFI), and uses the 2.4 GHz band, and the maximum shared bandwidth is 11 Mbit/s. At present, the indoor coverage of the products can generally reach to 30-50 m, and the outdoor coverage can reach to 100-200 m.
In recent years, with the higher and higher demands for the wireless access speed, bandwidth and data services of users, the interworking services between the 3G network and the WLAN network attract wide attention. The 3rd Generation Partnership Project (3GPP) also takes the 3G/WLAN interworking system as an additional standard of the 3GPP. Since the coverage of the WIFI network is limited, and as for a terminal, besides the WIFI module, other wireless communication modules (Modem) should also exist.
The prior art at least has following drawbacks that: the terminal directly accessing the Internet by the WIFI is unable to access a plurality of services of the Public Data Network (PDN), however the available access bandwidth provided by the cellular mobile communication network is limited, and particularly for services such as the video on demand, video broadcast and so on with a higher requirement for bandwidth, with too many problems to be dealt with, and is unable to implement various data services of the existing PDN well.